Earth-like exoplanet discovered around Proxima Centauri

lionking said:
But they may come to us. Why not? It's almost impossibly unlikely that intelligent life evolved on earth. It's equally almost impossibly unlikely that intelligent life evolved there, but several centuries more advanced. The more earth-like planets discovered, the less almost impossibly unlikely the chances become.
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Considering the time scales involved, it's very likely that if there are sentient life forms elsewhere in the universe, with a level of technology equivalent to our own or greater, they are pretty far away. We'd mostly find microbes, or dead civilisations.
 
The discussion about human adaptation to travelling to, and living on, exoplanets has been split to here. As the mechanism for splitting a thread is more akin to a chainsaw than a scalpel, there may be some posts that have gone to the split thread but should have stayed here, or posts not moved but should have been. Please do report these and I or another mod will move accordingly.
Posted By: Agatha
 
if the planet doesn't have a molten core and atmosphere, it's mostly likely forzen. Also, an 11-day year is not very practical for us.

Still - worth examining some more.
 
The Great Zaganza said:
if the planet doesn't have a molten core and atmosphere, it's mostly likely forzen. Also, an 11-day year is not very practical for us.

Still - worth examining some more.
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It'd keep Santa busy, and can you imagine doing your tax returns!

But we don't know how long a day is, could it even be tidal locked?
 
Within the next half century or so, what are the chances that, for Proxima Centauri b:
  • an atmosphere will be conclusively discovered?
  • some firm ranges of surface temperatures will be established?
  • the planet will be resolved, to at least a dozen or so pixels across?
  • some limits on the composition and density profile of the atmosphere will be established?
  • the existence of large bodies of surface water will be announced?

What sorts of telescopes etc would be needed to make the above discoveries (etc)? Can any existing telescopes (etc) be used for any such discoveries? Are there any planned facilities which could (within a half century or so)?

Please, less speculation, more science.
 
JeanTate said:
Within the next half century or so, what are the chances that, for Proxima Centauri b:
  • an atmosphere will be conclusively discovered?
  • some firm ranges of surface temperatures will be established?
  • the planet will be resolved, to at least a dozen or so pixels across?
  • some limits on the composition and density profile of the atmosphere will be established?
  • the existence of large bodies of surface water will be announced?

What sorts of telescopes etc would be needed to make the above discoveries (etc)? Can any existing telescopes (etc) be used for any such discoveries? Are there any planned facilities which could (within a half century or so)?

Please, less speculation, more science.
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As regards the atmosphere, it has been noted that if the planet is in a position to make a transit of the star as seen from Earth, then some important information about the atmosphere, including composition and thickness, may become available. I suppose some information about temperature can be inferred from the luminosity of the star and the distance of the planet from it, both already known. But the rest of the points you raise still look like the object of speculation at present.
 
JeanTate said:
an atmosphere will be conclusively discovered?
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Depends on if it transits. I think the discovers of the planets estimate a 1 or 2 percent chance of that. This planet is very close to an active star. I'd expect it's atmosphere is going to match the stars stellar wind.

JeanTate said:
the planet will be resolved, to at least a dozen or so pixels across?
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We can't yet resolve (in the sense you're using the word) the star it orbits as anything other than a single pixel. ETA: Nor can we resolve the larger stars in the same system.
 
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A single telescope 20000 meters across ought to resolve it
to a dozen pixels or so, if I did the math in my head right.
 
Solitaire said:
A single telescope 20000 meters across ought to resolve it
to a dozen pixels or so, if I did the math in my head right.
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...or a number of telescopes that kind of distance apart (or more) linked by computer. This could give us the necessary resolving power although it would very short on pure light-bucketry!


ETA:

The theoretical resolution of a telescope is calculated using the formula

R = 11.6 / D

where R is the the angular size of the object in arc-seconds and D is the diameter of the mirror/objective in centimeters.

In your example, the effective diameter of the telescope aperture/mirror is 20,000 meters (2,000,000 cm) so we can calculate that its theoretical resolution is 11.6 / 2,000,000 = 1.3 x 10-4 arc-seconds.

Sounds impressive, but a planet the size of the earth (approx 12,700 km in diameter) at a distance of 4 light years has an angular diameter of 7 × 10-5 arcseconds

A 20 km diameter telescope is too small by factor of two, and if you take account of Nyquists theorem, then by at least a factor of four.

IMO, you need to be thinking of an optical interferometer arrangement of hundreds, if not, thousands of kilometres across.
 
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RecoveringYuppy said:
<snip>

We can't yet resolve (in the sense you're using the word) the star it orbits as anything other than a single pixel. ETA: Nor can we resolve the larger stars in the same system.
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theprestige said:
What would it take to resolve? A network of optical telescopes throughout the solar system, in an interferometric array?
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smartcooky said:
...or a number of telescopes that kind of distance apart (or more) linked by computer. This could give us the necessary resolving power although it would very short on pure light-bucketry!


ETA:

The theoretical resolution of a telescope is calculated using the formula

R = 11.6 / D

where R is the the angular size of the object in arc-seconds and D is the diameter of the mirror/objective in centimeters.

In your example, the effective diameter of the telescope aperture/mirror is 20,000 meters (2,000,000 cm) so we can calculate that its theoretical resolution is 11.6 / 2,000,000 = 1.3 x 10-4 arc-seconds.

Sounds impressive, but a planet the size of the earth (approx 12,700 km in diameter) at a distance of 4 light years has an angular diameter of 7 × 10-5 arcseconds

A 20 km diameter telescope is too small by factor of two, and if you take account of Nyquists theorem, then by at least a factor of four.

IMO, you need to be thinking of an optical interferometer arrangement of hundreds, if not, thousands of kilometres across.
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Solitaire said:
A single telescope 20000 meters across ought to resolve it
to a dozen pixels or so, if I did the math in my head right.
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What if both versions of the Terrestrial Planet FinderWP were built?

Or the ESA's DarwinWP?

How feasible would it be to build something like either the TPF or Darwin, so as to resolve Proxima b, and have it produce good results before ~2065?

These sorts of projects have very long "cool idea! let's start planning" to "it's now in the hands of astronomers to run" elapsed times (though making something like this a national priority might speed things up a bit).
 
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